/**************************************************************************** * net/igmp/igmp_leave.c * * Copyright (C) 2010-2011, 2014, 2018 Gregory Nutt. All rights reserved. * Author: Gregory Nutt * * The NuttX implementation of IGMP was inspired by the IGMP add-on for the * lwIP TCP/IP stack by Steve Reynolds: * * Copyright (c) 2002 CITEL Technologies Ltd. * All rights reserved. * * Redistribution and use in source and binary forms, with or without * modification, are permitted provided that the following conditions * are met: * * 1. Redistributions of source code must retain the above copyright * notice, this list of conditions and the following disclaimer. * 2. Redistributions in binary form must reproduce the above copyright * notice, this list of conditions and the following disclaimer in the * documentation and/or other materials provided with the distribution. * 3. Neither the name of CITEL Technologies Ltd nor the names of its * contributors may be used to endorse or promote products derived from * this software without specific prior written permission. * * THIS SOFTWARE IS PROVIDED BY CITEL TECHNOLOGIES AND CONTRIBUTORS ``AS IS'' * AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE * ARE DISCLAIMED. IN NO EVENT SHALL CITEL TECHNOLOGIES OR CONTRIBUTORS BE * LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR * CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF * SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS * INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN * CONTRACT, STRICT LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) * ARISING IN ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE * POSSIBILITY OF SUCH DAMAGE. * ****************************************************************************/ /**************************************************************************** * Included Files ****************************************************************************/ #include #include #include #include #include #include #include #include #include #include #include "devif/devif.h" #include "igmp/igmp.h" #ifdef CONFIG_NET_IGMP /**************************************************************************** * Public Functions ****************************************************************************/ /**************************************************************************** * Name: igmp_leavegroup * * Description: * Remove the specified group address to the group. * * RFC 2236, 3. Protocol Description: * * "When a host leaves a multicast group, if it was the last host to * reply to a Query with a Membership Report for that group, it SHOULD * send a Leave Group message to the all-routers multicast group * (224.0.0.2). If it was not the last host to reply to a Query, it MAY * send nothing as there must be another member on the subnet. This is * an optimization to reduce traffic; a host without sufficient storage * to remember whether or not it was the last host to reply MAY always * send a Leave Group message when it leaves a group. Routers SHOULD * accept a Leave Group message addressed to the group being left, in * order to accommodate implementations of an earlier version of this * standard. Leave Group messages are addressed to the all-routers * group because other group members have no need to know that a host * has left the group, but it does no harm to address the message to the * group." * * ________________ * | | * | | * | | * | | * +--------->| Non-Member |<---------+ * | | | | * | | | | * | | | | * | |________________| | * | | | * | leave group | join group | leave group * | (stop timer, |(send report, | (send leave * | send leave if | set flag, | if flag set) * | flag set) | start timer) | * ________|________ | ________|________ * | |<---------+ | | * | | | | * | |<-------------------| | * | | query received | | * | Delaying Member | (start timer) | Idle Member | * +---->| |------------------->| | * | | | report received | | * | | | (stop timer, | | * | | | clear flag) | | * | |_________________|------------------->|_________________| * | query received | timer expired * | (reset timer if | (send report, * | Max Resp Time | set flag) * | < current timer) | * +-------------------+ * * Assumptions: * The network is locked. * ****************************************************************************/ int igmp_leavegroup(struct net_driver_s *dev, FAR const struct in_addr *grpaddr) { struct igmp_group_s *group; int ret; DEBUGASSERT(dev && grpaddr); /* Find the entry corresponding to the address leaving the group */ group = igmp_grpfind(dev, &grpaddr->s_addr); ninfo("Leaving group: %p\n", group); if (group) { DEBUGASSERT(group->njoins > 0); group->njoins--; /* Take no further actions if there are other members of this group * on this host. */ if (group->njoins > 0) { return OK; } /* Cancel the timer and discard any queued Membership Reports. * Canceling the timer will prevent any new Membership Reports from * being sent; clearing the flags will discard any pending Membership * Reports that could interfere with the Leave Group. */ wd_cancel(&group->wdog); CLR_SCHEDMSG(group->flags); CLR_WAITMSG(group->flags); IGMP_STATINCR(g_netstats.igmp.leaves); /* Send a leave if the flag is set according to the state diagram */ if (IS_LASTREPORT(group->flags)) { ninfo("Schedule Leave Group message\n"); IGMP_STATINCR(g_netstats.igmp.leave_sched); ret = igmp_waitmsg(group, IGMP_LEAVE_GROUP); if (ret < 0) { nerr("ERROR: Failed to schedule message: %d\n", ret); } } /* Free the group structure (state is now Non-Member */ igmp_grpfree(dev, group); /* And remove the group address from the drivers MAC filter set */ igmp_removemcastmac(dev, (FAR in_addr_t *)&grpaddr->s_addr); return OK; } /* Return ENOENT if the address is not a member of the group */ ninfo("Return -ENOENT\n"); return -ENOENT; } #endif /* CONFIG_NET_IGMP */